Loop Filter Combining ADC and Slicer TEDs for Stable Timing Recovery
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Solution Overview
Problem
Existing timing recovery loops in digital communication systems face instability due to the complementary advantages and disadvantages of ADC-TED and Slicer-TED, leading to poor reception performance and phase jitter, especially during transitions in autocorrelation characteristics.
Innovation Solution
A loop filter and timing recovery apparatus that combines multiple timing error detectors (ADC-TED and Slicer-TED) with 2N independently configurable gain parameters, allowing for full combination of their advantages and suppression of their disadvantages, thereby stabilizing reception performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ADC-TED is used for timing recovery, then timing error detection can be performed on the raw ADC output signal, but the reception performance becomes unstable due to noise and interference
Solution Approach 1:
The patent combines ADC-TED and Slicer-TED into a unified timing recovery system. The ADC-TED provides timing error detection on raw ADC output while the Slicer-TED provides detection on equalized signals. By merging their outputs through a loop filter, the system achieves both high timing detection accuracy and stable reception performance, resolving the contradiction between measurement precision and reliability.
2Reliability
If Slicer-TED is used for timing recovery, then the timing error detection is based on equalized signals, but phase jitter increases and reception performance deteriorates
Solution Approach 1:
The patent merges the output of Slicer-TED with ADC-TED output in the loop filter. The Slicer-TED provides stable timing recovery based on equalized signals, while the ADC-TED component adds timing error detection accuracy from raw ADC output. This combination resolves the contradiction between reliability and measurement precision by leveraging the strengths of both approaches.
3Reliability
If multiple timing error detectors are combined, then the advantages of each detector can be utilized, but the system complexity increases
Solution Approach 1:
The loop filter is designed as a multi-functional component that simultaneously processes outputs from both ADC-TED and Slicer-TED. It performs filtering, gain adjustment, and combination operations in a single unified structure, enabling the system to leverage multiple timing error detectors without proportionally increasing complexity. This resolves the contradiction between reliability improvement and device complexity.
4Reliability
If gain parameters are configured to suppress noise from ADC-TED, then reception stability improves, but the timing error detection responsiveness decreases
Solution Approach 1:
The patent implements dynamic gain adjustment in the loop filter, where the gain parameters are not fixed but adapt based on signal conditions. This allows the system to suppress noise from ADC-TED during stable periods while maintaining responsiveness during transitions. The dynamic nature of the gain parameters resolves the contradiction between reliability and speed by allowing the system to optimize performance for different operating conditions.
Data Source
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AI summary
A loop filter, and a timing recovery method and apparatus. The loop filter comprises: N input terminals, configured to receive N first signals, wherein N is any integer greater than or equal to two; a source filter, comprising an integrated signal terminal and an addition terminal; a first gain processing module, configured to perform first gain processing on the N first signals to obtain a second signal, and output the second signal to the addition terminal; a second gain processing module, configured to perform second gain processing on the N first signals to obtain a third signal, and output the third signal to the integrated signal terminal; and a source filter, configured to perform integration on the third signal received by the integrated signal terminal to obtain a fourth signal, and obtain a fifth signal according to the second signal and the fourth signal received by the addition terminal.